BuildTimeInfo Setup

BuildTimeInfo.tt

<#@ template debug="false" hostspecific="false" language="C#" #>
<#@ assembly name="System.Core" #>
<#@ import namespace="System" #>
<#@ output extension=".cs" #>
<# 
string datePattern = "fffssmmHHddMMyyyy";
string buildTime = DateTime.Now.ToString(datePattern);
string humanReadableBuildTime = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss:fff");
#>using System;
using System.Globalization;

public class BuildTimeInfo {
	/// <summary>
	/// The time this assembly was built (<#= humanReadableBuildTime#>)
	/// </summary>
	private static readonly DateTime buildTime = DateTime.ParseExact("<#= buildTime#>", "<#= datePattern#>", CultureInfo.InvariantCulture);

	/// <summary>
	/// Get the time this assembly was built (<#= humanReadableBuildTime#>)
	/// </summary>
	public static DateTime BuildTime {
		get 
		{
			return buildTime;
		}
	}

	/// <summary>
	/// A string description of when this assembly was built (returns "<#= humanReadableBuildTime#>")
	/// </summary>
	public const string BuildTimeString = "<#= humanReadableBuildTime#>";
}

Project-With-BuildTimeInfo-Class.csproj

<?xml version="1.0" encoding="utf-8"?>
<Project>
  <ItemGroup>
    <None Include="RunT4.bat" />
    <None Include="BuildTimeInfo.tt">
      <Generator>TextTemplatingFileGenerator</Generator>
      <LastGenOutput>BuildTimeInfo.cs</LastGenOutput>
    </None>
  </ItemGroup>
  <PropertyGroup>
    <PreBuildEvent>..\..\RunT4.bat ..\..</PreBuildEvent>
  </PropertyGroup>
</Project>

RunT4.bat

@echo off
REM äöäé
SETLOCAL ENABLEDELAYEDEXPANSION

:: set the working dir (default to current dir)
set wdir=%cd%
if not (%1)==() set wdir=%1

:: set the file extension (default to vb)
set extension=cs
if not (%2)==() set extension=%2

echo executing transform_all from %cd%
:: create a list of all the T4 templates in the working dir
dir %wdir%\*.tt /b /s > t4list.txt

echo the following T4 templates will be transformed:
type t4list.txt

:: transform all the templates
for /f "delims=" %%d in (t4list.txt) do (
set file_name=%%d
set file_name=!file_name:~0,-3!.%extension%
echo:  \--^> !file_name!    
echo Running "%COMMONPROGRAMFILES(x86)%\microsoft shared\TextTemplating\12.0\TextTransform.exe" -out "!file_name!" "%%d"
"%COMMONPROGRAMFILES(x86)%\microsoft shared\TextTemplating\12.0\TextTransform.exe" -out "!file_name!" "%%d"
)

echo transformation complete

Tested with Visual Studio Professional 2013